I modified the proxy host cache we already had and were using for
websocket csp headers to also include the wildcard app host, then used
those for frame-src policies.
I did not add frame-ancestors, since if I understand correctly, those
would go on the app, and this middleware does not come into play there.
Maybe we will want to add it on workspace apps like we do with cors, if
we find apps are setting it to `none` or something.
Closes https://github.com/coder/internal/issues/684
* fix: allow ports in wildcard url configuration
This just forwards the port to the ui that generates urls.
Our existing parsing + regex already supported ports for
subdomain app requests.